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Biomedical subjects

D Carpenter

Publications and source records attributed to D Carpenter.

At least 19 recordsLinked to original sources
PubMed1992

Acting up and physical illness: temporal patterns and emerging structure.

Many psychoanalytic writers have viewed acting out and somatization as alternate routes for the discharge of uncontained aggressive impulses in borderline patients. In order to investigate this empirically, we tracked the occurrence of two related behaviors--acting up and physical illness--over the course of one patient's long-term hospitalization. Daily scores on these variables were analyzed using a time series procedure. Results indicated that as treatment progressed, acting up and physical illness became more synchronized, and this occurred just prior to symptom remission. Material from psychotherapy suggested that these behavioral changes were associated with the patient's increased ability to verbalize aggressive impulses in the context of fantasy and memory.

Acting Out↗
PubMed1991

Very low concentrations of acetylcholine and GABA modulate transmitter responses.

Acetylcholine and GABA, at extremely low concentrations (10(-14) to 10(-8) M) which do not induce electrical responses, each modulate the chloride-dependent responses of Aplysia neurons to higher concentrations of the same transmitters. Low concentrations of acetylcholine cause a reduction of the response to both acetylcholine and GABA, while low concentrations of GABA cause a facilitation of responses to both acetylcholine and GABA. These effects have a clear threshold, are slow in onset, reversible with prolonged washing, and blocked by cooling.

Acetylcholine↗
PubMed1990

Biochemical and functional abnormalities in hypercholesterolemic rabbit platelets.

This study was designed to elucidate changes in rabbit platelet lipids induced by a cholesterol rich diet and to explore the possible correlation of these lipid changes with platelet abnormalities. Pronounced biochemical alterations were observed when serum cholesterol levels of 700-1000 mg% were reached. Hypercholesterolemic (HC) platelets contained 37% more neutral lipids and 16% less phospholipids than the controls. Lysolecithin, cholesterol esters and phosphatidylinositol (PI) levels were increased in HC platelets, and the levels of phosphatidylcholine (PC) were decreased. The cholesterol/phospholipid molar ratio of lipidemic platelets increased from 0.55 +/- 0.011 to 0.89 +/- 0.016 (P less than 0.01) in eight weeks. HC platelets had 90% more arachidonic acid (AA) in the PI than normal platelets. No significant changes in AA of PC were observed. Platelet function was monitored by the uptake and release of [14C]serotonin in platelet rich plasma (PRP), using varying concentrations of collagen as an aggregating agent. The uptake of [14C]serotonin in HC and normal platelets ranged from 78-94%. The percent of [14C]serotonin released from normal and HC platelets was proportional to the concentration of collagen. However, lipidemic platelets were hyperreactive to low concentrations of collagen. Incorporation of 50 microM acetylsalicylic acid into the aggregating medium suppressed the release of [14C]serotonin in normal PRP by more than 90%, but had only a partial effect on lipidemic PRP.

Animals↗
PubMed1990

Modulation of HLA-DR expression in epithelial cells by interleukin 1 and estradiol-17 beta.

Both ultrapure human interleukin-1 (IL-1) and Escherichia coli derived recombinant IL-1 alpha and beta consistently induced the expression of major histocompatibility class II (HLA-DR) molecules in a human endometrial and a breast carcinoma cell line. [35S]Methionine incorporation into IL-1 induced, immunoprecipitable HLA-DR molecules demonstrated de novo synthesis of both light and heavy chains of the HLA-DR molecules. Lipopolysaccharide, recombinant interleukin-2 and recombinant interleukin-6 failed to induce HLA-DR expression in these epithelial cells. In contrast to the dramatic effect on HLA-DR expression, IL-1 had no effect on the epithelial cell proliferation. Pretreatment of T47D cells with estradiol-17 beta significantly decreased the IL-1 induced HLA-DR expression, and pretreatment of IL-1 with an IL-1 specific antibody, neutralized IL-1 action. These studies demonstrate that a cytokine (IL-1) and a sex steroid hormone estradiol-17 beta can interact to regulate the expression of HLA-DR molecules in epithelial cells.

Epithelium↗
PubMed1990

The intracolonic bypass tube for left colon and rectal trauma. The avoidance of a colostomy.

Traumatic perforations of the left colon and rectum are most frequently managed by procedures that include the formation of a colostomy. Primary repair without colostomy is much less commonly employed. We report nine patients with traumatic perforations of the left colon and rectum treated with the intracolonic bypass tube (ICBT) without concomitant colostomy. In all these patients we believe the standard treatment would have included fecal diversion. Four patients sustained blunt trauma and five sustained penetrating trauma. Healing of the colonic anastomosis occurred in all cases, and the ICBTs were passed per rectum between the tenth and nineteenth days postoperatively. On the basis of this study, we conclude that the ICBT has a role in the treatment of selected injuries of the left colon and rectum as a safe means of avoiding a colostomy.

Adult↗
PubMed1989

Megakaryocytopenia in W/Wv mice is accompanied by an increase in size within ploidy groups and acceleration of maturation.

Megakaryocytopoiesis was evaluated in W/Wv mice and their normal +/+ littermates to analyze the mechanisms by which normal platelet production is maintained in W/Wv mice even though numbers of megakaryocytes are low. Relative sizes of megakaryocytes, and their nuclei and cytoplasm, were measured microscopically in bone marrow smears, and the ploidy of the same cells was measured by two-wavelength microspectrophotometry. Maturation rate of megakaryocytes was estimated after they were labeled with tritiated thymidine. W/Wv megakaryocytes were macrocytic: average cell size was increased in each ploidy group. The increase in cytoplasmic area exceeded that of the nucleus. Further analysis of the predominant 16N ploidy group revealed that the increase in average cell size was due to depletion of cells of small size. Megakaryocytes matured more rapidly than normal in W/Wv mice. These results showed that megakaryocyte size and ploidy can be regulated separately. They suggest that alterations in cell growth and maturation may be mechanisms by which the organism can compensate for a deficiency in numbers of megakaryocytes, but they do not define the mechanism by which the deficiency may be sensed or by which the compensatory changes may be mediated. This is a US government work. There are no restrictions on its use.

Animals↗
PubMed1988

Morphological and kinetic abnormalities of platelets in hypercholesterolemic rabbits.

Hypercholesterolemia (HC = hypercholesterolemia or hypercholesterolemic) was produced in rabbits by feeding them diets supplemented with cholesterol and peanut oil. Platelet counts and volumes, white cell counts, reticulocyte counts, and hematocrits were determined at intervals for 8-12 weeks in blood from HC animals and controls on a normal rabbit diet. Microthrombocytosis was a consistent occurrence in the presence of HC, developing as early as 2 weeks into the diet. Microthrombocytosis was generally associated with normal platelet counts, but mild thrombocytosis occurred late in the diet at the time of the highest levels of serum cholesterol (greater than 1300 mg/dl). Platelets from HC rabbits were morphologically normal by transmission electron microscopy. Survivals of 51Cr-labeled platelets from HC and non-HC rabbits were measured in HC and non-HC recipients. The results identified an intrinsic defect in the ability of HC platelets to survive in the circulation. They also confirmed previous findings of an environmental defect in HC that causes shortened platelet survival.

Animals↗
PubMed1988

Variation in indirect cell-mediated lympholysis.

The ability of an allograft recipient to respond to donor mononuclear cells in an indirect cell-mediated lympholysis (ICML) assay is an in vitro correlate of allograft rejection, but the value of this correlation depends upon the assay's reliability. We had observed inconsistency in the cytotoxic response of normal human mononuclear cells (MNC) to the same allogeneic stimulator MNC when cytotoxicity was measured repeatedly on different occasions by micro-ICML. We, therefore, investigated the extent and reasons for this inconsistency. Method variation, determined by duplicate ICML of 18 stimulator: responder MNC, was not statistically significant. Variation in cytotoxicity over time was greater but still not statistically significant. The contribution to method variation of 51Cr release from 3 different sets of target cells, cultured and labeled in duplicate, was minimal (6.33%). We then asked if in vitro generation of effector MNC under laboratory conditions was a major cause of ICML variation. We tested this using a stable transplant's in vivo sensitized effector cells against donor MNC in a direct CML (DCML) and obtained consistent results. Finally, to gain an understanding of some of the factors which might influence the generation of in vitro cytotoxicity, we measured the frequencies of cell surface antigens (DR, TAC, transferrin, Leu 2 and 3) concomitantly with ICML on day 6 of culture. Statistical analysis of the results led us to conclude that the micro-ICML is reproducible. The magnitude of lysis depends upon activated target cells (TAC- and transferrin-positive) and an increase in the proportion of helper/inducer to cytotoxic/suppressor T-lymphocytes during effector cell generation.

Antigens, Surface↗
PubMed1988

Megakaryocytes increase in size within ploidy groups in response to the stimulus of thrombocytopenia.

Experiments were done to determine if sizes of megakaryocytes within a defined maturation stage were strictly determined by amount of nuclear DNA. Normal mice, mice recovering from an acute episode of thrombocytopenia induced by a single injection of heterologous antiplatelet serum (APS), and mice with sustained thrombocytopenia from daily injections of APS were examined. Areas of mature megakaryocytes were measured in bone marrow smears stained with polychromatic stains. The nuclear DNA content of the same cells was then measured microspectrophotometrically after staining by the Feulgen reaction. Normal megakaryocytes showed a trimodal, lognormal distribution of nuclear chromophore, corresponding to 8n, 16n, and 32n with smaller numbers of 4n and 64n cells; 16n was the predominant ploidy class. In response to thrombocytopenia, ploidy values shifted: the proportions of 8n and 16n cells decreased; 32n and 64n cells increased; 128n megakaryocytes occasionally appeared. These shifts were accompanied by an increase in the average size of all megakaryocytes. In addition to shifts to higher ploidy values, megakaryocytes within ploidy groups became larger than normal megakaryocytes of the same ploidy especially in the mice with sustained thrombocytopenia. These findings show that megakaryocyte size in thrombocytopenic mice is influenced by factors other than the ploidy and maturity of the cell.

Anemia↗
PubMed1988

Survival of rabbit platelets labeled with gallium 67.

The viability of rabbit platelets labeled with radioactive gallium was determined to analyze the feasibility of using platelets labeled with gallium 68 as an imaging reagent for positron emission tomography. Platelets were labeled with a complex of the longer lived gallium 67 and mercaptopyridine-N-oxide (MPO) or with sodium chromate Cr 51. Their survival after transfusion was measured. Labelling efficiency of 67Ga-MPO was 6.5% to 45.8% (26.8% +/- 2.8%) when platelets were suspended in saline solution, but was much lower (1.6% +/- 0.8%) in plasma. Platelets labeled with either radioisotope in a saline medium survived as well as platelets labeled with 51Cr in plasma. Recovery values 1 hour after transfusion and mean platelet survivals were 68.6% +/- 4.9% and 3.4 +/- 0.2 days for 67Ga in saline solution, 76.5% +/- 6.8% and 3.8 +/- 0.5 days for 51Cr in saline solution, and 73.7% +/- 7.4% and 3.6 +/- 0.5 days for 51Cr in plasma. Labeled platelet concentrates always contained extra radioactivity not firmly bound to viable platelets. A postlabeling wash in saline solution did not reduce this contamination and resulted in reduction of the number of viable platelets. The results showed that rabbit platelets labeled with 67Ga-MPO survived in the circulation as well as those labeled by a standard protocol with sodium chromate Cr 51.

Animals↗
PubMed1987

A note on the effect of gamma-rays on cefamandole and oxacillin.

The feasibility of the radiation sterilization of two beta-lactam antibiotic powders, cefamandole nafate and oxacillin sodium, has been examined by subjecting them to a range gamma-radiation doses, followed by chemical and microbiological analyses. It would appear feasible to radiation sterilize oxacillin sodium. The radiation sterilization of cefamandole nafate may be realistic at low doses or under conditions that minimize radiolysis.

Cefamandole↗
PubMed1986

Effects of intermittent pneumatic calf compression on postoperative thrombin and plasmin activity.

A previous study of neurosurgical patients demonstrated an imbalance between thrombin and plasmin action following surgery. The present study was designed to determine the effect of intermittent pneumatic calf compression on postoperative enzyme activity. Fibrinopeptide A (FPA) and B beta 1-42 levels, reflecting thrombin and plasmin action respectively, were measured daily in patients undergoing elective craniotomy. Two of 9 patients not receiving calf compression developed positive fibrinogen leg scans, while none of 5 patients receiving prophylaxis had positive scans. Calf compression was associated with a markedly altered pattern of changes in the fibrinopeptide values following surgery. Without compression, there was perturbation of the balance between thrombin and plasmin action on the day after surgery as reflected by an increase in the FPA/B beta 1-42 ratio. In contrast, in those receiving prophylaxis there was no change in this ratio on the first postoperative day. Calf compression both blunted the mean postoperative increase in the FPA level (1.8 nM vs 4.7 nM; p less than .05) and augmented the mean B beta 1-42 value (3.0 nM vs 0.2 nM; p less than .05) so that the mean increase in the FPA/B beta 1-42 ratio was only 0.1 with calf compression as compared to 2.2 without it (p less than .05). Systemic modulation of both the coagulation and fibrinolytic pathways thus occurred in association with calf compression.

Adult↗
PubMed1976

Heterogeneity of Staphylococcus aureus enterotoxin B as a function of growth stage: implications for surveillance of foods.

Staphylococcus aureus was grown in a fermentor under controlled conditions of pH, oxygenation, and temperature, while the higher-molecular-weight products of its growth were continuously removed across ultrafiltration membranes. These products were examined by single and double gel diffusion and immunoelectrophoresis against a variety of available anti-enterotoxin B antisera. All antisera examined were polyvalent for S. aureus antigens. However, two electrophoretically distinct proteins were the major reactants with the antisera. One of these was present in early- to mid-log-phase cultures. After mid-log growth was achieved, both were present but in continuously changing proportions. This observation was repeated with a variety of growth conditions and media. A significant part of the physicochemical heterogeneity of enterotoxin B observed over the past 20 years is thus correlated with the growth phase of the organism. Taken together, these facts are used to argue for a two-step rationale for the detection of food-borne staphylococcal disease: (i) screening for a presumptive hazard by analysis for any antigen, toxin, or enzyme of S. aureus in a foodstuff and (ii) confirmation of the hazard by identifying the presence of an enterotoxin using a combination of physicochemical and serological techniques.

Antigens, Bacterial↗
PubMed1975

Effect of ouabain and potassium-free solution on mammalian thermosensitive afferents in vitro.

Studies have been performed on the afferent fibers innervating the scrotal skin of the rat to test the hypothesis that the generator potential mechanism underlying cold thermosensitivity of these afferent fibers is an electrogenic sodium pump. In these experiments a pudendal nerve-scrotal skin preparation was isolated from the animal and maintained in oxygenated mammalian Ringer's where composition could be varied and drugs added. Application of ouabain resulted in an increae in the discharge of cold sensitive afferent fibers which was more pronounced at 38--41 degrees C than at temperature below 30 degrees C. In most of the cases transient accelerations on cooling were reduced, but often a transient response to warming appeared. The effects of ouabain administration were reversible. Removal of extracellular K at 35 degrees C resulted in an increased discharge of cold sensitive afferents. This observation is consistent with the effects of ouabain, since removal of extracellular K also block Na transport. The generator potential mechanism underlying cold sensitivity of these afferent fibers appears to be an electrogenic Na pump.

Afferent Pathways↗